A number of mechanisms have been devised for protecting a USB connector in a thumb drive memory device. As discussed in U.S. Pat. No. 6,808,400 to Tu, the prior art solution used a removable cap that snapped over the USB connector. See Tu, at column 1, lines 30 through 40, and FIG. 1 (“Prior Art”). The Tu patent discloses a USB connector at the end of a printed circuit board (“PCB”) slidably disposed within a case. In one embodiment, a spring urges the PCB toward a position in which the USB connector extends beyond the case, and a “pushing button” with an arm having a “buckling piece” holds the PCB in a retracted position. Another embodiment disclosed in Tu reverses the spring and buckle arrangement to hold the PCB and USB connector in the extended position. Other embodiments of TU use a lipstick-style mechanism. The lipstick-style mechanism relies on a rotating knob that turns a threaded shaft which screws into a threaded bore connected to the PCB. When the knob is turned, the shaft causes the PCB to extend or retract.
A button mechanism is disclosed in U.S. Pat. No. 7,422,454 to Tang et al., relying on a “middle carrier” that is located within halves of a casing, whereby the carrier can be moved within the case, thereby extending or retracting a USB connector.
The present retractable thumb drive mechanisms relying on a button to extend and retract the USB connector provide no mechanical advantage. The lipstick-style mechanism provides some mechanical advantage, but requires two hands to operate and usually requires too many turns.